The present disclosure relates to subject matter contained in priority Japanese Patent Application Nos. 2000-364826 and 2001-243420, filed on Nov. 30, 2000 and Aug. 10, 2001 respectively, the contents of which is herein expressly incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a prismatic battery module and a method for manufacturing the same. More particularly, the invention relates to a prismatic battery module which is made by connecting a plurality of cells together and designed to reduce an internal resistance, and a method for manufacturing the same.
2. Description of Related Art
A conventional rechargeable battery module made by connecting a plurality of cells together, each having an individual cell case, has a problem that the connection path between the cells is long and the number of connection points is large and each of the connection points has small cross-sectional area, thereby increasing the component resistance leading to the increase of internal resistance thereof.
In consideration of the aforementioned conventional problem, the inventors of this invention have proposed a prismatic battery module 100 including a plurality of cells 2 as shown in FIGS. 12 and 13. Reference numeral 3 denotes a prismatic battery case constructed in such a manner that a plurality of prismatic cell cases 4 of cells 2, each cell case having short lateral walls and long lateral walls, are integrally connected together in series, and each pair of cell cases shares short lateral walls thereof as a separation wall 5, and further, an upper opening of each of the cell cases is closed by a unitary lid 6. In the upper portions of outer short lateral walls of the outermost cell cases and the separation wall 5 between the adjacent cell cases 4 are formed connection holes 7. Within each of the cell cases 4, an electrode plate group 8 constructed by alternately stacking rectangular positive and negative electrode plates interposing a separator therebetween is accommodated together with an electrolyte. The positive and the negative electrode plates constituting the electrode plate group 8 project from the electrode plate group in opposite directions to form a lead portion 9a of the positive electrode plate and a lead portion 9b of the negative electrode plate, respectively. To the side ends of the lead portions 9a, 9b are connected collector plates 10a, 10b, respectively, by welding or the like.
In the upper portions of the collector plates 10a, 10b are formed connection projections 11 to be fitted into the connection holes 7, and the connection projections 11 of the collector plates 10a, 10b as positive and negative poles respectively are connected to each other between the adjacent cell cases 4 by welding. Furthermore, in the connection holes 7 of the outer short lateral walls of the outermost cell cases 4 are mounted connection terminals 12 as either a positive or negative pole, and a connection projection 13 of the connection terminal 12 and the connection projection 11 of either the collector plate 10a or 10b are connected to each other by welding. Thus, a plurality of cells 2 accommodated in the prismatic battery case 3 are connected together in series.
Additionally, in the lid 6 are provided a communication path 14 for balancing the internal pressure between the cell cases 4, a safety vent (not shown) for discharging the pressure when the internal pressure of the cell case 4 exceeds a predetermined value and a sensor fixing hole 15 for fixing a temperature sensor thereto to detect the temperature of the cell 2.
According to the above-described construction of battery, since the electrical communication path from the positive and negative electrode plates of the electrode plate group 8 to the respective lead portions 9a, 9b is short and further the adjacent lead portions 9a, 9b of the associated electrode plate groups are connected to each other via the associated collector plate 10a, 10b within the prismatic battery case 3, the connection path between the electrode plate groups is short and the number of connection points is small, thereby allowing the prismatic battery module to reduce the component resistance included therein and in proportion thereto, reduce the internal resistance.
However, although the prismatic battery module 100 shown in FIGS. 12 and 13 is constructed so that the connection path from the positive and negative electrode plates to the respective collector plates 10a, 10b via the respective lead portions 9a, 9b is short, as is denoted by arrows in FIG. 14, the adjacent collector plates 10a, 10b of the associated electrode plate groups are connected at one point of both ends of the connection projections 11 located at the upper portions of the adjacent collector plates by welding and therefore, there have been seen problems that the entire connection path between the adjacent electrode plate groups becomes longer and in addition, the internal resistance between the cells becomes higher since the electrical communication between the adjacent collector plates is performed at only one point. Furthermore, there have also been seen problems that the collector plates 10a, 10b employed in the battery 100 increases the manufacturing cost of battery correspondingly, and further, it is necessary to arrange the collector plates 10a, 10b on both sides of the electrode plate group 8 and to form the upper portion of the collector plates 10a, 10b so as to project beyond the upper end of the electrode plate group 8, thereby forcing enlargement of the volume of the cell case 4.
In consideration of the above problems seen in the conventional technique, an object of the present invention is to provide a prismatic battery module in which the internal resistance per cell is reduced, and a method for manufacturing the same.
A prismatic battery module according to a first aspect of the invention includes a prismatic battery case constructed by connecting a plurality of prismatic cell cases together in series, each pair of cell cases sharing a separation wall; an electrode plate group formed by alternately stacking positive and negative electrode plates interposing a separator therebetween and further forming lead portions by projecting one side portion of the positive electrode plates and one side portion of the negative electrode plates in opposite directions, respectively; and collectors connected to the lead portions on both sides of the electrode plate group, in which the prismatic battery module is further constructed such that adjacent electrode plate groups are connected to each other by connecting adjacent collectors to each other through a connection aperture formed in a central portion of the separation wall and a sealing material is applied to each space between each of the separation walls around the connection aperture and each of the collectors. As the adjacent collectors are connected through the connection aperture formed in the central portion of the separation wall, the electrical communication path between the electrode plate groups becomes shorter allowing the reduction of the internal resistance and the upper portion of the collector is not required to project from the electrode plate group, resulting in the volume reduction of prismatic battery case.
A prismatic battery module according to a second aspect of the invention includes a prismatic battery case having a single internal space therein; an electrode plate group formed by alternately stacking positive and negative electrode plates interposing a separator therebetween and further forming lead portions by projecting one side portion of the positive electrode plates and one side portion of the negative electrode plates in opposite directions, respectively; and collectors connected to the lead portions on both sides of the electrode plate group, in which the prismatic battery module is further constructed such that a plurality of electrode plate groups are connected together by connecting adjacent collectors of adjacent electrode plate groups to each other and arranging the plurality of electrode plate groups alongside in series within the prismatic battery case, and the single internal space is partitioned into a plurality of cell cases by applying a sealing material to each space between outer periphery of the adjacent collectors connected to each other and a wall surface of the prismatic battery case. As the plurality of electrode plate groups are connected to each other via the entire surface of the adjacent collectors respectively, the electrical communication path between the electrode plate groups becomes shorter allowing the extensive reduction of the internal resistance of cell. In the above-described construction of battery, the plurality of electrode plate groups, which are integrally connected together in series, are disposed in the prismatic battery case and further, each outer periphery of the adjacent collectors is sealed by a sealing material, thereby forming sealed cell cases for electrode plate groups respectively.
A prismatic battery module according to a third aspect of the invention includes a prismatic battery case constructed by connecting a plurality of prismatic cell cases together in series, each pair of cell cases sharing a separation wall; an electrode plate group formed by alternately stacking positive and negative electrode plates interposing a separator therebetween and further forming lead portions by projecting one side portion of the positive electrode plates and one side portion of the negative electrode plates in opposite directions, respectively; collectors connected to the lead portions on both sides of the electrode plate group; and an electroconductive plate provided in at least one sidewall of the prismatic battery case and facing adjacent cell cases, in which the electroconductive plate is connected to adjacent collectors of adjacent electrode plate groups. As entire surface of one side portion or both side portions of adjacent collectors is connected together via the electroconductive plate, the electrical communication path between the electrode plate groups becomes shorter allowing the reduction of the internal resistance of cell and further, the upper portion of the collector is not required to project from the electrode plate group, resulting in the volume reduction of prismatic battery case.
A prismatic battery module according to a fourth aspect of the invention includes a prismatic battery case constructed by connecting a plurality of prismatic cell cases together in series, each pair of cell cases sharing a separation wall; an electrode plate group formed by alternately stacking positive and negative electrode plates interposing a separator therebetween and further forming lead portions by projecting one side portion of the positive electrode plates and one side portion of the negative electrode plates in opposite directions, respectively; a plurality of connecting rods formed so as to penetrate the lead portions on both sides of the electrode plate group, respectively; and an electroconductive plate provided in at least one sidewall of the prismatic battery and facing adjacent cell cases, in which each of the plurality of connecting rods and the electroconductive plate are connected to each other. As at least one of both end portions of the plurality of connecting rods penetrating the lead portions of the electrode plate group connects the lead portions of adjacent electrode plate groups to each other via the electroconductive plate, the electrical communication path between the electrode plate groups becomes shorter allowing the reduction of the internal resistance of cell and further, the upper portion of the collector is not required to project upwardly from the electrode plate group, resulting in the volume reduction of prismatic battery case.
A prismatic battery module according to a fifth aspect of the invention includes a prismatic battery case constructed by connecting a plurality of prismatic cell cases together, the plurality of cell cases being arranged alongside one by one in addition to being spaced apart from each other and being constructed in such a manner that one of both ends of one of the cell cases and one of both ends of another one of the cell cases adjacent to the one of the cell cases are spatially connected to each other through a communicating space at a position of a connection portion to thereby form a zigzag chain of the plurality of cell cases; an electrode plate group formed by alternately stacking positive and negative electrode plates interposing a separator therebetween and further forming lead portions by projecting one side portion of the positive electrode plates and one side portion of the negative electrode plates in opposite directions, respectively; and an electroconductive plate for providing electrical communication between a plurality of electrode plate groups by connecting the plurality of electrode plate groups together in such a manner that one of both lead portions of one of adjacent electrode plate groups and one of both lead portions of the other of the electrode plate groups are connected via the electroconductive plate to thereby form a zigzag chain of the plurality of electrode plate groups, the zigzag chain of the electrode plate groups being arranged alongside so as to have the same pitch as that of an arrangement of the plurality of cell cases, in which the plurality of electrode plate groups connected together via associated electroconductive plates are disposed in the prismatic battery case and each space between the electroconductive plate and the prismatic battery case at the connection portion between the cell cases is sealed with a sealing material. As the adjacent collectors of the associated electrode plate groups are connected to each other via the electroconductive plate over the entire surface of the collectors, the electrical communication path between the electrode plate groups becomes shorter allowing the reduction of the internal resistance, and further, each space between the prismatic battery case and the electroconductive plate at the connection portion between the cell cases is sealed by the sealing material, whereby the cell cases are isolated from each other and further, the space between the cell cases can be utilized as a coolant passage, resulting in the achievement of high cooling performance of prismatic battery module.
A prismatic battery module according to a sixth aspect of the invention includes a prismatic battery case constructed by connecting a plurality of prismatic cell cases together, the plurality of cell cases being arranged alongside one by one in addition to being spaced apart from each other and being constructed in such a manner that one of both ends of one of the cell cases and one of both ends of another one of the cell cases adjacent to the one of the cell cases are connected to each other to thereby form a zigzag chain of the plurality of cell cases; an electrode plate group formed by alternately stacking positive and negative electrode plates interposing a separator therebetween and further forming lead portions by projecting one side portion of the positive electrode plates and one side portion of the negative electrode plates in opposite directions, respectively; collectors connected to the lead portions on both sides of the electrode plate group; and an electroconductive plate provided in a cell case connection portion of the prismatic battery case and facing adjacent cell cases, in which the electroconductive plate provides electrical connection between adjacent collectors of associated electrode plate groups. As the adjacent collectors of the associated electrode plate groups are connected to each other via the electroconductive plate over the entire surface of the collectors, the electrical communication path between the electrode plate groups becomes shorter allowing the reduction of the internal resistance of cell, and further, the space between the cell cases can be utilized as a coolant passage, resulting in the achievement of high cooling performance of prismatic battery module.
A prismatic battery module according to a seventh aspect of the invention includes a prismatic battery case constructed by connecting a plurality of prismatic cell cases together in series, via associated separation walls made of a crank-shaped electroconductive plate, each of the separation walls having connection surfaces being arranged along a direction of an arrangement of the cell cases in addition to being formed in a central portion in a width direction of the cell case; an electrode plate group formed by alternately stacking positive and negative electrode plates interposing a separator therebetween and further forming lead portions by projecting one side portion of the positive electrode plates and one side portion of the negative electrode plates in opposite directions, respectively; and collectors connected to the lead portions on both sides of the electrode plate group, in which the prismatic battery case accommodates the plurality of cell cases such that associated parts of adjacent collectors of adjacent electrode plate groups, the adjacent electrode plate groups being disposed in adjacent cell cases, faces each other interposing the connection surfaces therebetween and the adjacent collectors are connected to each other by welding the adjacent collectors to associated connection surfaces interposing the associated connection surfaces therebetween. As the adjacent collectors are connected via the crank-shaped electroconductive plate constituting the separation wall between the cell cases, the electrical communication path between the electrode plate groups becomes shorter allowing the reduction of the internal resistance of cell and the upper portion of the collector is not required to project upwardly from the electrode plate group, resulting in the achievement of corresponding volume reduction of prismatic battery case.
A method for manufacturing a prismatic battery module according to an eighth aspect of the invention, includes the steps of: forming a prismatic battery case having a plurality of cell cases therein, the plurality of cell cases being connected together in series via associated separation walls and connection apertures, each connection aperture being located in a central portion of each of the separation walls; forming an electrode plate group having positive and negative electrode plates therein so as to project lead portions of the positive and negative electrode plates therefrom on both sides thereof; connecting collectors to the lead portions of the electrode plate group; and disposing the electrode plate group in the cell case in such a manner that adjacent collectors of associated electrode plate groups are connected to each other via each of the connection apertures and at the same time, each space formed around the adjacent collectors is sealed.
A method for manufacturing a prismatic battery module according to a ninth aspect of the invention, includes the steps of: forming a prismatic battery case having a space for forming a plurality of prismatic cell cases therein; forming an electrode plate group having positive and negative electrode plates therein so as to project lead portions of the positive and negative electrode plates therefrom on both sides thereof; connecting collectors to the lead portions of the electrode plate group; connecting a plurality of electrode plate groups together, via adjacent collectors of associated electrode plate groups; and disposing the plurality of electrode plate groups, the plurality of electrode plate groups being integrally connected together in series, in the prismatic battery case in a state of individual opposing portions consisting of the adjacent collectors and an inner wall of the prismatic battery case interposing a sealing material therebetween.
A method for manufacturing a prismatic battery module according to a tenth aspect of the invention, includes the steps of: forming a prismatic battery case having a plurality of cell cases integrally therein and an electroconductive plate facing adjacent cell cases in addition to being located between adjacent end portions of the adjacent cell cases; forming an electrode plate group having positive and negative electrode plates therein so as to project lead portions of the positive and negative electrode plates therefrom on both sides thereof; connecting one of collectors and connecting rods to the lead portions of the electrode plate group; and a step for inserting the electrode plate group in the cell case and connecting selected one from the collectors and the connecting rods to the electroconductive plate.
A method for manufacturing a prismatic battery module according to an eleventh aspect of the invention, includes the steps of: forming a prismatic battery case having a single internal space therein; forming an electrode plate group having positive and negative electrode plates therein so as to project lead portions of the positive and negative electrode plates therefrom on both sides thereof; connecting electroconductive plates to the lead portions of the electrode plate group and integrally connecting a plurality of electrode plate groups together in series via the electroconductive plates; and disposing the plurality of electrode plate groups in the prismatic battery case in a state of individual opposing portions consisting of each of the electroconductive plates and an inner wall of the prismatic battery case interposing a sealing material therebetween, thereby partitioning the internal space into a plurality of cell cases.
While novel features of the invention are set forth in the preceding, the invention, both as to organization and content, can be further understood and appreciated, along with other objects and features thereof, from the following detailed description and examples when taken in conjunction with the attached drawings.